针对传统Al-Mg-Si-Cu系合金时效硬化速率仍不能很好满足汽车轻量化的应用要求，本项目创新性地利用熔体原位复合法制备了含有一定量弥散粒子的新型Al-Mg-Si-Cu-Zn系合金。通过成分设计、热加工和预处理过程调控等，该系合金可充分利用Mg-Si和Mg-Zn等相的均匀/非均匀形核协同作用而表现出优异的快速时效硬化特性。本项目拟采用DSC、HRTEM、三维原子探针以及力学性能测量等手段，对该系合金时效硬化速率、沉淀析出行为和组织结构等进行精细表征。据此建立成分-工艺-组织-性能间的定量关系，进而掌握并提出该系合金的快速时效硬化机制和多相协同强化理论模型，最终建立变形铝合金快速时效硬化理论和过程调控技术。本研究不仅为快速时效硬化型铝合金的进一步开发、加工、表征和应用提供重要指导，而且也为更好地研究其它时效强化型铝合金时效硬化速率的过程调控及其相关机制等共性关键科学问题提供重要理论支撑。

In view of the age-hardening response of traditional Al-Mg-Si-Cu alloys cannot meet the requirements of automotive applications, an advanced Al-Mg-Si-Cu-Zn alloy with a certain amount of dispersed particles was developed by the in-situ synthesis method. After controlling and optimizing the composition, thermomechanical processing and pre-treatments, the prepared alloy can display an excellent age-hardening response by the cooperative action of homogeneous and heterogeneous nucleations of Mg-Si and Mg-Zn precipitates. The following topics, age-hardening response, precipitation behaviors, microstructure and phase structure, will be characterized by DSC, HRTEM, three-dimensional atom probe and mechanical property measurements. Accordingly, the quantitative relationship between composition, processing, microstructure and properties can be established, and then, both the fast age-hardening response mechanism and multi-phase strengthening model of the alloy can be put forward from it, and finally establishing the fast age-hardening response theory of wrought Al alloys and forming the technique of process controlling. Hopefully, the systematical researches in this proposal can give a good instruction on the further development, processing, characterization and application of the wrought Al alloys with a characteristic of fast age-hardening response, and also provide a theoretical support for studying on the controlling method of age-hardening response and related key scientific issues in other age-hardening Al alloys.